Correction of severely deformed hammertoe attributable to silastic implant failure with use of calcaneal autograft

Few studies exist investigating surgical hammertoe correction salvage procedures regarding poor outcomes secondary to silastic implant failure. We present a case of a patient who presented to our clinic with a grossly deformed digit after undergoing several silastic implant procedures. The patient wanted to salvage the toe and elected for surgical intervention. Surgical planning consisted of a V-Y skin plasty with interposition of calcaneal autograft. This allowed restoration of anatomic dimensions and function of the patient's digit. We present this operative technique as a viable method of salvaging failed hammertoe correction procedures.

Abstract 1469: The inflammatory pre-metastatic niche in reliably metastatic models of triple negative breast cancer

The purpose of this study was to evaluate Triple Negative Breast Cancer (TNBC) murine models to use for investigations of the pre-metastatic niche. We selected two murine TNBC based on published gene expression studies which demonstrated molecular profiles that mirrored human breast tumor subtypes. The 2225L murine tumor has similar gene expression patterns to human tumors of the basal-like phenotype. When 2225L was implanted in the mammary fat pad or sc flank of syngeneic naïve Balb/c female mice, no metastases were observed. Tumors were subsequently resected at approximately 600-800 mm3 to promote the growth of seeded metastases. To select for a consistently metastatic 2225L variant, primary tumors or lung metastases from the most consistently metastatic 2225L tumors were serially passaged sc. The resulting variant (2225LM) is highly metastatic, with lung metastases in 90% (43/48) of mice from the most recent 4 cohorts compared to 27% (47/176) of mice in 66 previous passages. Metastases were not observed at any other site. We also studied the T11 murine tumor, which is representative of the claudin-low phenotype. However, when tested for mouse pathogens prior to implantation, T11 was positive for lactate dehydrogenase elevating virus (LDEV). To eliminate LDEV, T11 tumors were serially passaged into athymic nude rats. The resulting LDEV-free T11 tumor was used for in vivo studies. After sc implantation of T11 in Balb/c mice, consistent lung metastases were observed (89%; 24/27 mice). Tumor-infiltrating immune cell subsets were assessed using flow cytometry. CD11b+ Ly6G- and CD11b+ Ly6G+ cells comprised the majority of tumor-infiltrating immune cells and both subsets were more prevalent in 2225LM than T11. Infiltrating lymphoid (CD3+) cells were a minor component of both tumors. In preliminary studies to quantify lung-infiltrating immune cells, levels of CD11b+ Ly6G+ cells were 1.5 fold higher in 2225LM and T11 tumor-bearing mice compared to controls. Prior to the development of frank metastases (12-30 days post-2225L implant), lung analysis by ELISA showed a steady increase in the neutrophil chemoattractant KC and the pro-tumor M2/N2 chemokine marker MCP-1. Analysis of lungs with visible 2225LM metastases detected increased levels of KC (6-27 fold) and MCP-1 (11-23 fold), when compared to naïve mice. These chemokines were not elevated at non-metastatic sites (i.e. kidney). To conclude, our lab has selected, developed and characterized two TNBC mouse models. Both tumor cell lines are reliable metastatic models of TNBC and will be used to further characterize the inflammatory microenvironment of the pre-metastatic niche, including the continuum of gene expression patterns and changing cellular components.

Citation Format: Kassondra Balestrieri, H Keith Pittman, Matthew Britt, Mohamed Ramez, Nasreen Vohra, Kathryn Verbanac. The inflammatory pre-metastatic niche in reliably metastatic models of triple negative breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1469.

Comparison of Hallux Interphalangeal Joint Arthrodesis Fixation Techniques: A Retrospective Multicenter Study

Few studies have investigated the complications that occur after hallux interphalangeal joint arthrodesis. The present study evaluated complications in 152 patients aged 18 to 80 years from 2005 to 2012 from 4 different academic institutions after hallux interphalangeal joint arthrodesis. Overall, 65.8% of the patients had ≥1 complication. Infections occurred in 16.5%, dehiscence in 12.5%, and reoperations in 27.0%. The clinical nonunion rate was ≥17.8%, and the radiographic nonunion rate was ≥13.8%. After logistic regression analysis, only the study site and peripheral neuropathy were associated with having ≥1 complication (p < .01 and p < .05, respectively). Single screw fixation compared with other fixation did not have a statistically significant influence on the postoperative complications. However, when fixation was expanded to 4 categories, single screw fixation had lower infection and reoperation rates than either crossed Kirschner wires or other fixation category but not compared with crossed screws on multivariate logistic regression analysis. Although additional studies are warranted, the findings from the present study might aid in both the prognosis of complications and the support of the use of a single screw over crossed Kirchner wire fixation in hallux interphalangeal joint arthrodesis.

Neomycin is an agonist at a polyamine site on the N-methyl-D-aspartate receptor

Neomycin appears as a full agonist and spermidine as a partial agonist at the site where polyamines enhance 1-[1-(2-thienyl)cyclohexyl][3H]piperidine ([3H]TCP) binding on the N-methyl-D-aspartate (NMDA) receptor. Other aminoglycosides also enhance [3H]TCP binding with efficacies roughly proportional to the number of primary amine groups. The polyamine antagonists ifenprodil and arcaine inhibit enhancement of [3H]TCP binding by spermidine or neomycin. The inhibition of [3H]TCP binding by arcaine is apparently competitively reduced by neomycin and spermidine, supporting a common site. Diethylenetriamine (previously described as a polyamine antagonist) may be a partial agonist. Enhancement by neomycin or spermidine is not additive to that of Mg2+, consistent with competition of Mg2+ and spermidine or neomycin at the site where these compounds enhance [3H]TCP binding. Polyamines also enhance the binding of the competitive antagonist 2-(2-carboxypiperazin-4-yl)[3H]propyl-1-phosphonic acid ([3H]CPP). Neomycin, which does not enhance [3H]CPP binding, inhibits the enhancement by spermidine. That this site is distinct from the site where spermidine and neomycin increase [3H]TCP binding is supported by different pharmacology. Arcaine and diethylenetriamine do not inhibit spermidine enhancement of [3H]CPP binding. Mg2+ also does not compete with the spermidine enhancement of [3H]CPP binding. Ifenprodil inhibits the spermidine enhancement of [3H]CPP binding. The data suggest two or more polyamine sites, with arcaine selective for the site that enhances [3H]TCP binding. Neomycin is an agonist at one polyamine site and antagonist to the second.

Inhibition of the B to Z transition in poly(dGdC).poly(dGdC) by covalent attachment of ethidium: kinetic studies

The photoaffinity analogue ethidium monoazide was used to prepare samples of poly(dGdC).poly(dGdC) containing covalently attached ethidium. The effects of both noncovalently and covalently bound ethidium on the kinetics of the NaCl-induced B to Z transition in poly(dGdC).poly(dGdC) was examined using absorbance and fluorescence spectroscopy to monitor the reaction. Covalently and noncovalently attached ethidium were equal in the extent to which they reduce the rate of the B to Z transition. By using fluorescence to selectively monitor the fate of noncovalently bound ethidium over the course of the transition, we found that ethidium completely dissociates as the reaction proceeds, but at a rate that lags behind the conversion of the polymer to the Z form. These experiments provide evidence for the redistribution of noncovalently bound ethidium over the course of the B to Z transition, leading to the development of biphasic reaction kinetics. The observed kinetics suggest that the primary effect of both covalently and noncovalently bound ethidium is on the nucleation step of the B to Z transition. The reduction in the rate of the B to Z transition by noncovalently or covalently bound ethidium may be quantitatively explained as resulting from the reduced probability of finding a drug-free length of helix long enough for nucleation to occur. As necessary ancillary experiments, the defined length deoxyoligonucleotides (dGdC)4, (dGdC)5, and (dGdC)6 were synthesized and used in kinetic experiments designed to determine the nucleation length of the B to Z transition, which was found to be 6 bp. The activation energy of the B to Z transition was demonstrated to be independent of the amount of covalently bound ethidium and was found to be 21.2 +/- 1.1 kcal mol-1. Covalent attachment of ethidium was observed to increase the rate of the reverse Z to B transition, presumably by locking regions of the polymer into a right-handed conformation and thereby providing nucleation sites from which the Z to B conversion may propagate.

Reflex sympathetic dystrophy after clavicle fracture: case report

Reflex sympathetic dystrophy (RSD) of the anterior chest wall is a rare entity. A MEDLINE search in all languages of the world's literature from 1966 to the present yielded no report of the association of clavicle fracture with this pain syndrome. Two cases are presented and the anatomic variations of the supraclavicular nerves in relation to the clavicle are discussed.

Stereoselectivity for the (R)-enantiomer of HA-966 (1-hydroxy-3-aminopyrrolidone-2) at the glycine site of the N-methyl-D-aspartate receptor complex

HA-966 (1-hydroxy-3-aminopyrrolidone-2) is an antagonist at the glycine allosteric site of the N-methyl-D-aspartate receptor ionophore complex. Unlike presently known glycine antagonists, HA-966 is chiral. We report stereoselectivity for the (R)-enantiomer at the glycine antagonist site. In [3H]glycine binding, the (R)-enantiomer has an IC50 of 4.1 +/- 0.6 microM. The racemic mixture has an IC50 of 11.2 +/- 0.5 microM, whereas (S)-HA-966 has an IC50 greater than 900 microM. In glycine-stimulated [3H]1-[1-(2- thienyl)cyclohexyl]piperidine binding, the (R)-enantiomer inhibits with an IC50 of 121 +/- 61 microM, whereas the racemic mixture has an IC50 of 216 +/- 113 microM and (S)-HA-966 is inactive. The inhibition by (R)-HA-966 can be prevented by the addition of glycine. (R)-HA-966 and racemic HA-966, but not (S)-HA-966, also prevent N-methyl-D-aspartate cytotoxicity in cortical cultures. The (R)-enantiomer and, less potently, the (S)-enantiomer inhibit N-methyl-D-aspartate-evoked [3H]norepinephrine release from rat hippocampal slices (IC50 values of about 0.3 mM and 1.6 mM, respectively), but only the inhibition by (R)-HA-966 is reversed by added glycine. In glutamate-evoked contractions of the guinea pig ileum, (R)-HA-966 causes a glycine-reversible inhibition (IC50 of about 150 microM), whereas (S)-HA-966 is much less potent (IC50 of greater than 1 mM). These results demonstrate stereoselectivity of the glycine antagonist site of the N-methyl-D-aspartate receptor complex in a variety of tissues and assays. The stereoselectivity also confirms the specificity of N-methyl-D-aspartate receptors in glutamate-evoked contractions of the guinea pig ileum, and supports their similarity to central N-methyl-D-aspartate receptors.

Stereoselective enhancement by (R)-HA-966 of the binding of [3H]CPP to the NMDA receptor complex

The enantiomers of the strychnine-insensitive glycine antagonist, HA-966 (1-hydroxy-3-amino-pyrrolidone-2), stereoselectively enhance binding of the N-methyl-D-aspartate (NMDA) competitive antagonist, [3H]CPP (3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid) to rat brain synaptosomal membranes. The enhancement by the more potent (R)-HA-966 is competitively inhibited by the glycine antagonist 7-chlorokynurenic acid and noncompetitively by the polyamine spermine. Thus, (R)-HA-966, apparently at the glycine site, enhances the binding of antagonist to the NMDA receptor, possibly through a mechanism partially in common with that of spermine.

Site and sequence specificity of the daunomycin-DNA interaction

The site and sequence specificity of the daunomycin-DNA interaction was examined by equilibrium binding methods, by deoxyribonuclease I footprinting studies, and by examination of the effect of the antibiotic on the cleavage of linearized pBR322 DNA by restriction endonucleases PvuI and EcoRI. These three experimental approaches provide mutually consistent results showing that daunomycin indeed recognizes specific sites along the DNA lattice. The affinity of daunomycin toward natural DNA increases with increasing GC content. The quantitative results are most readily explained by binding models in which daunomycin interacts with sites containing two adjacent GC base pairs, possibly occurring as part of a triplet recognition sequence. Deoxyribonuclease I footprinting studies utilizing the 160 base pair (bp) tyrT DNA fragment and 61 and 53 bp restriction fragments isolated from pBR322 DNA further define the sequence specificity of daunomycin binding. Specific, reproducible protection patterns were obtained for each DNA fragment at 4 degrees C. Seven protected sequences, ranging in size from 4 to 14 bp, were identified within the tyrT fragment. Relative to the overall tyrT sequence, these protected sequences were GC rich and contained a more limited and distinct distribution of di- and trinucleotides. Within all of the protected sequences, a triplet containing adjacent GC base pairs flanked by an AT base pair could be found in one or more copies. Nowhere in the tyrT fragment did that triplet occur outside a protected sequence. The same triplet occurred within seven out of nine protected sequences observed in the fragments isolated from pBR322 DNA. In the two remaining cases, three contiguous GC base pairs were found. We conclude that the preferred daunomycin triplet binding site contains adjacent GC base pairs, of variable sequence, flanked by an AT base pair. This conclusion is consistent with the results of a recent theoretical study of daunomycin sequence specificity [Chen, K.-X., Gresh, N., & Pullman, B. (1985) J. Biomol. Struct. Dyn. 3, 445-466]. Adriamycin and the beta-anomer of adriamycin produce the same qualitative pattern of protection as daunomycin with the tyrT fragment. Daunomycin inhibits the rate of digestion of pBR322 DNA by PvuI (recognition sequence 5'-CGATCG-3') to a greater extent than it does EcoRI (recognition sequence 5'-GAATTC-3'), a finding consistent with the conclusions derived from our footprinting studies. Our results, as a whole, are the clearest indication to date that daunomycin recognizes a specific DNA sequence as a preferred binding site.

The interaction of the beta-anomer of doxorubicin with B and Z DNA

Equilibrium and kinetic studies on the interaction of daunorubicin, doxorubicin, and the beta-anomer of doxorubicin with B and Z form DNA were made using spectroscopic and fluorometric methods. The beta-anomer of doxorubicin binds more weakly to calf thymus DNA than do the parent compounds, with a binding constant over 2 orders of magnitude lower than that found for doxorubicin. The ionic strength dependence of the binding constant is identical for daunorubicin and the beta-anomer of doxorubicin, indicating that the electrostatic contribution to the binding free energy is the same for the two compounds. Rate constants for steps along the dissociation pathway are larger for the beta-anomer relative to the parent compounds, indicating a shorter lifetime for the beta-anomer-DNA complex. Daunorubicin and doxorubicin were equally effective as inhibitors of the rate of the B to Z transition of polydeoxyguanylic-deoxycytidylic acid (poly(dGdC] in 3.0 M NaCl. Both compounds bound cooperatively to poly (dGdC) under high salt conditions that initially favor the Z conformation. In contrast, the beta-anomer of doxorubicin did not inhibit the rate of the B to Z transition under these conditions, and would not bind to poly(dGdC) in 3.0 M NaCl. The beta-anomer did inhibit the rate of the transition of poly(dGm5dC) to the Z form in 50 mM NaCl, 2.5 mM MgCl2, although not as effectively as daunorubicin. Further, binding of the beta-anomer to poly(dGm5dC) under these conditions was cooperative, although the beta-anomer was clearly a less efficient allosteric effector on the B to Z transition than was daunorubicin. These results emphasize the importance of the stereochemistry of the daunosamine residue in the specific and preferential binding of anthracycline antibiotics to B form DNA.

Sinus contamination with Pseudomonas paucimobilis: a pseudoepidemic due to contaminated irrigation fluid

During a five-week period, Pseudomonas paucimobilis was isolated from maxillary sinus irrigation washes of four patients who attended an ear, nose and throat clinic. The saline irrigation solution was found to be contaminated with the same organism. Further investigation demonstrated the organism in a majority of hospital sinks surveyed. Although P. paucimobilis was isolated from clinical specimens, the presence of the organism did not appear to have clinical significance.